Captiva |
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• | Signs of being twisted, bent, nicked, or cracked |
• | Scratches or abrasion on the rod bearing seating surface |
5.1. | Using an outside micrometer, take two measurements of the piston pin in the area of the connecting rod contact. |
5.2. | Using an inside micrometer, measure the connecting rod piston pin bore. |
5.3. | Subtract the piston pin diameter from the piston pin bore diameter. |
5.4. | The clearance should not be more than 0.021 mm (0.0008 in). |
• | Cracked ring lands, skirts, or pin bosses |
• | Ring grooves for nicks, burrs that may cause binding |
• | Warped or worn ring lands |
• | Eroded areas at the top of the piston (1) |
• | Scuffed or damaged skirts (2) |
• | Worn gudgeon pin bores (3) |
5.1. | Piston pin bores and pins must be free of varnish or scuffing. |
5.2. | Use an outside micrometer to measure the piston pin in the piston contact areas. |
5.3. | Using an inside micrometer, measure the piston pin bore. |
5.4. | Subtract the measurement of the piston pin bore from the piston pin. The clearance should be within 0.002-0.012 mm (0.00007-0.00047 in). |
5.5. | If the clearance is excessive, determine which component is out of specification. |
6.1. | Place the piston ring in the area of the bore where the piston ring will travel (approximately 25 mm or 1 inch down from the deck surface). Be sure the ring is square with the cylinder bore by positioning the ring with the piston head. |
6.2. | Measure the end gap of the piston ring with feeler gauges (1). Compare the measurements with those provided below: |
• | The top compression ring end gap should be 0.20-0.40 mm (0.0060-0.015 in). |
• | The second compression ring end gap should be 0.35-0.55 mm (0.0137-0.0216 in). |
• | The oil ring end gap should be 0.25-0.76 mm (0.0098-0.029 in). |
6.3. | If the clearance exceeds the provided specifications, the piston rings must be replaced. |
6.4. | Repeat the procedure for all the piston rings. |
7.1. | Roll the piston ring entirely around the piston ring groove. If any binding is caused by a distorted piston ring, replace the ring. |
7.2. | With the piston ring on the piston, use feeler gauges (1) to check clearance at multiple locations. |
7.3. | The clearance between the surface of the top piston ring and the ring land should be no greater than 0.075 mm (0.0030 in). |
7.4. | If the clearance is greater than specifications, replace the piston ring. |
7.5. | If the new ring does not reduce the top ring side clearance to 0.075 mm (0.0030 in) or less, install a new piston. |
11.1. | Using an outside micrometer (2), measure the width of the piston 14.5 mm (0.570 in) above the bottom of the piston skirt at the thrust surface perpendicular to the centre line of the gudgeon pin. |
11.2. | Compare the measurement of the piston to its original cylinder by subtracting the piston width from the cylinder diameter. |
11.3. | The proper clearance specification for the piston is 0.010-0.041 mm (0.0006-0.0016 in). |
Note: Measurements of all components should be taken with the components at normal room temperature.
For proper piston fit, the engine block cylinder bores must not have excessive wear or taper. A used piston and pin set may be reinstalled if, after cleaning and inspection, they are within specifications.© Copyright Chevrolet. All rights reserved |